Weak electron correlations and itinerant $5f$ electrons in ${\mathrm{UFeGa}}_5$: A high-resolution ARPES and DFT study

Uranium compounds have long been of significant interest in condensed matter physics due to their diverse and often exotic properties, including heavy-fermion behavior, non-Fermi-liquid characteristics, quantum criticality, and unconventional superconductivity. These phenomena arise from the complex interplay between crystal structure, hybridization of localized $5f$ electrons with conduction electrons, and electron-electron correlations. Here, we present a comprehensive study of the electronic structure of ${\mathrm{UFeGa}}_{5}$, a layered uranium intermetallic compound, using high-resolution angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) calculations. Three-dimensional electronic structure of ${\mathrm{UFeGa}}_{5}$ was systematically studied and fine structures of the $\mathrm{U}5f$ bands near the Fermi energy were clearly resolved. Our results reveal that ${\mathrm{UFeGa}}_{5}$ exhibits a predominantly itinerant nature of $5f$ electrons, with strong band dispersion and significant contributions to the Fermi surface. Theoretical calculations assuming itinerant $5f$ electrons are in excellent agreement with the experimental ARPES data, confirming the weak electron correlation effects in this compound. Temperature-dependent ARPES measurements further demonstrate that the $f$ electrons retain itinerant across the studied temperature range (7.5 to 100 K).